The color patterns on cephalopods are controlled in large part by chromatophores, pigment-filled cells controlled by the animal's muscles. Michael Bok, a graduate student at the University of Maryland, Baltimore County, filmed this video of a dead Longfin Inshore Squid (Loligo pealeii) still-active chromatophores expanding and contracting, and set the whole thing to Johann Pachelbel's "Canon in D Major." Insert HypnoSquid jokes where appropriate.